1. Field of the Invention
The present invention relates to a system in which charge air for an automotive engine is compressed and cooled by the same rotating machine.
2. Disclosure Information
Automotive history is replete with designs for charge boosting of reciprocating combustion engines. A veritable plethora of systems have been used, including turbochargers, superchargers, and other such devices. A common problem associated with turbocharging and supercharging is the necessity of removing heat from the compressed air charge. Heat should be reduced from the charge for a couple of reasons, such as increasing density of the air charge, and helping to prevent knock. Unfortunately, the need for charge air heat extraction, which is commonly called intercooling, greatly increases the complexity of the charge air system because the charge air flowing from the turbocharger, supercharger or other device, must pass through a heat exchanger, which of course must be supplied not only with the charge air but also with a cooling fluid, whether it be ambient air or some other fluid. Accordingly, it has not generally been possible to close couple superchargers to engines very readily in any package efficient manner, given the necessity or at least the desirability, to use charge air intercooling.
A system according to the present invention solves the problems associated with prior boosting and charge air cooling systems by combining these functions into a single rotating machine. As will be explained in further detail below, the charge compression machine may comprise either a turbocharger or a supercharger, but in any event, the present machine uses refrigeration actually incorporated within the compression machine or booster to accomplish charge air cooling, thereby producing a very lightweight, compact, energy efficient, and powerful engine assist device.
An engine having a charge air conditioning system comprising a charge air booster, a refrigerant-to-air heat exchanger integral with the charge air booster, and a refrigeration system for supplying refrigerant to the refrigerant-to-air heat exchanger.
A charge air booster according to the present invention may comprise a supercharger driven by the engine directly and mechanically, or a turbocharger driven by exhaust gas from the engine, or a supercharger driven indirectly by an electric motor or hydraulically. In any event the refrigerant is preferably furnished to the heat exchanger as a liquid. The liquid may comprise either a liquid which does not change state in its course through the refrigerant-to-air heat exchanger, or a more traditional refrigerant which does change state from a liquid to a gas on its course through the refrigerant-to-air heat exchanger. In the latter case, the heat exchanger may comprise an evaporator which is mounted within the charge air booster, and with the refrigeration system providing liquid refrigerant to the evaporator, so that at least some of the refrigerant changes to a gas while the refrigerant is flowing through the evaporator so as to extract heat from air flowing through the charge booster. In the event that the booster comprises a centrifugal compressor, the evaporator may be mounted within a cover section of the compressor. As such, the evaporator may comprise an annular flow passage having an inlet for liquid refrigerant, an outlet for vaporized refrigerant, and an inner wall comprising a portion of the cover of the compressor. In the event that a liquid is used for the refrigerant, the annular flow passage feature may be retained. The flow passage will incorporate an inlet and outlet for liquid.
If a refrigeration system using a change of phase refrigerant is used as part of the current system, the refrigeration system may be used to provide refrigerant not only to the intercooler but also to an evaporator comprising a portion of a passenger cabin climate control system. In this case, the refrigerant system will of course be powered by the engine of the vehicle.
A charge air conditioning system with intercooling according to the present invention may be applied to a V-type engine. The supercharger and inner cooler may thus have outlets for providing chilled and compressed air to both banks of a V-type engine.
A method of providing compressed and thermally densified air charge to an engine includes the steps of filtering an air stream flowing into an engine, measuring the mass of air flowing into the engine, simultaneously compressing and extracting heat from the air charge, and conducting the compressed and thermally densified air to the engine.
It is an advantage of the present invention that air may both be compressed and chilled in a single machine taking up less space, weighing less and using less energy than prior art systems for compressing and intercooling charge air furnished to an engine.
It is a further advantage of the present invention that the present system will reduce costs associated with charge air compressing and intercooling.
Other advantages, as well as objects of the present invention will become apparent to the reader of this specification.